:root {
  /* Temperature: 0 = cold (blue), 1 = on top of me (red). */
  --heat: 0.3;
  --to-hot: calc(var(--heat) * 100%);
  --cold: oklch(0.90 0.05 250);
  --hot: oklch(0.86 0.10 25);
  --cold-strong: oklch(0.52 0.16 255);
  --hot-strong: oklch(0.56 0.20 27);
  --bg: color-mix(in oklab, var(--hot) var(--to-hot), var(--cold));
  --accent: color-mix(in oklab, var(--hot-strong) var(--to-hot), var(--cold-strong));
  --bg2: color-mix(in oklch, var(--bg) 75%, var(--accent));
  --fg: #142033;
  --muted: #4a5568;
  --card: rgb(255 255 255 / 0.72);
  --line: rgb(20 32 51 / 0.12);
  --accent-fg: #fff;
  color-scheme: light dark;
  transition: --heat 1.2s ease;
}
@property --heat { syntax: '<number>'; inherits: true; initial-value: 0.3; }
@media (prefers-color-scheme: dark) {
  :root {
    --cold: oklch(0.26 0.06 255);
    --hot: oklch(0.30 0.10 25);
    --cold-strong: oklch(0.70 0.14 250);
    --hot-strong: oklch(0.70 0.18 27);
    --bg2: color-mix(in oklch, var(--bg) 82%, var(--accent));
    --fg: #eef2f8;
    --muted: #a7b1c2;
    --card: rgb(10 14 22 / 0.55);
    --line: rgb(255 255 255 / 0.12);
    --accent-fg: #0b0f17;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; min-height: 100%; }
body {
  font: 17px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, "Hiragino Sans", "Noto Sans JP", sans-serif;
  color: var(--fg);
  background: radial-gradient(120% 80% at 50% 0%, var(--bg2), var(--bg)) fixed, var(--bg);
}
.stage {
  max-width: 34rem;
  margin: 0 auto;
  padding: max(24px, env(safe-area-inset-top)) 16px max(24px, env(safe-area-inset-bottom));
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-height: 100dvh;
}
header h1 { font-size: clamp(2rem, 8vw, 3rem); line-height: 1.1; margin: 0.5rem 0 0.25rem; letter-spacing: -0.02em; }
.tagline { margin: 0; color: var(--muted); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 20px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.fine { font-size: 0.875rem; color: var(--muted); margin: 0.5rem 0 0; }

button, .secondary {
  font: inherit;
  border-radius: 999px;
  border: 1px solid var(--line);
  padding: 0.6rem 1.1rem;
  background: transparent;
  color: var(--fg);
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
}
button.primary { background: var(--accent); color: var(--accent-fg); border: 0; font-weight: 600; width: 100%; padding: 0.9rem; font-size: 1.1rem; }
button.link { border: 0; padding: 0; text-decoration: underline; color: var(--muted); font-size: 0.875rem; }
button:disabled { opacity: 0.5; cursor: default; }
input:not([type="checkbox"]) {
  font: inherit; min-width: 12rem; flex: 1;
  padding: 0.6rem 0.9rem; border-radius: 999px;
  border: 1px solid var(--line); background: var(--card); color: var(--fg);
}
.row { display: flex; gap: 8px; margin-top: 6px; flex-wrap: wrap; }
.row > button { flex: 0 0 auto; }
a { color: var(--accent); }

.trend { font-size: clamp(2rem, 10vw, 3.25rem); font-weight: 800; line-height: 1.1; margin: 0 0 16px; letter-spacing: -0.02em; min-height: 1.1em; }
.distance { font-size: 1.25rem; font-weight: 600; margin: 16px 0 0; font-variant-numeric: tabular-nums; }
.thermo { height: 14px; border-radius: 999px; background: linear-gradient(90deg in oklab, var(--cold-strong), var(--hot-strong)); position: relative; overflow: hidden; }
.thermo-fill { position: absolute; inset: 0 0 0 auto; background: var(--card); width: calc((1 - var(--heat)) * 100%); transition: width 1s ease; backdrop-filter: grayscale(1); }
#map { margin-top: 12px; }

.message { margin: 0; padding: 12px 16px; border-radius: 14px; background: var(--card); border: 1px solid var(--line); }
.account form { margin-top: 8px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; }
.account form#login { display: block; }
.account form[hidden] { display: none; }
footer { margin-top: auto; color: var(--muted); font-size: 0.875rem; }
select { font: inherit; color: var(--fg); background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 2px 6px; }

dl.kv { display: grid; grid-template-columns: max-content 1fr; gap: 4px 12px; margin: 12px 0 0; font-size: 0.875rem; }
dl.kv dt { color: var(--muted); }
dl.kv dd { margin: 0; overflow-wrap: anywhere; }
code { font-size: 0.85em; overflow-wrap: anywhere; }
label.toggle { display: flex; gap: 10px; align-items: center; margin-top: 14px; }

@keyframes pulse { 50% { transform: scale(1.04); } }
.trend.burning { animation: pulse 1.2s ease-in-out infinite; }
@media (prefers-reduced-motion: reduce) { .trend.burning { animation: none; } :root, .thermo-fill { transition: none; } }
.steps { padding-left: 1.25rem; }
.steps li { margin: 0.5rem 0; }
.steps .row { margin-top: 8px; }
input[type="checkbox"] { width: 1.25rem; height: 1.25rem; flex: none; accent-color: var(--accent); }